Regulating apparatus



Dec. 4, 1945. M, A. EDWARDS REGULATING APPARATUS Filed March 25, 1944 2 Sheets-Sheet l al 7//////////V//// In 4 5 4 Inventor: Martin A'.Edwards,

His ttorney.

REGULAT I NG APPARATUS Filed March 25, 1944 2 Sheets-Sheet 2 Inventor Martin A. Edwards,

H s Attorney.

Patented Dec. 4, 1945 2.390.084 REGULATING APPARATUS Martin A. Edwards, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application March 25, 1944, Serial No. 528,122

30 Claims.

My invention relates to re ulating app fi. and more particularly to speed responsive governing apparatus for prime movers, such as internal combustion engines, turbines. and the like. The invention is especially applicable to gasor Diesel-electric power systems of the type commonly used in self-propelled vehicles.

Gasor Diesel-electric power systems for locomotives or other self-propelled vehicles ordinarily comprise a prime mover, such as a Diesel or other internal combustion engine, arranged to drive a generator from which power is supplied to one or more traction motors. Such a system is inherently subject to great and sudden changes of power demand upon the prime mover as the load upon the traction motors is changed in accelerating, braking, coasting and reversing. Such varying conditions of operation, coupled with the fact that the electrical system of such a vehicle has approximately the same power capacity as the prime mover, makes it particularly easy and, at the same time, particularly dangerous to overload or underload the engine. A need has long been recognized for an improved engine governing system and apparatus for maintaining the engine speed substantially constant under such 1cl'inclliitions of widely and rapidly varying engine Accordingly, it is a general object of my invention to provide a new and improved prime mover governing apparatus capable of quickly follgwing large and rapid changes of prime mover It is a further object of my invention to provide new and improved means for stabilizing the operation of a prime mover governing apparatus thereby to prevent overshooting of the control point and consequent hunting of the apparatus.

I have illustrated my invention herein by way of example as applied to a gas-electric vehicle propulsion system. The governing apparatus of larly to Fig. 1, the vehicle power system illustrated comprises a prime mover i0 0! the internal combustion engine type arranged to drive, through a common shaft l I, a main generator l2 and a generator exciter i 3. An output circuit for the armature I2a of the generator I2 is completed through the armatures and field windings of a pair of electric traction motors l6 and I1. The output circuit of the generator l2 includes a line switch 22 which may, if desired, be actuated by any suitable electromagnetic control system. It will be understood of course that the representation of a pair of traction motors l6 and I1 is purely diagrammatic, and that each motor shown on the drawings may represent either a single motor or a group of motors arranged either in series or parallel circuit relation.

It is well understood that in an internal combustion engine of the type herein contemplated the available horsepower output is a function of the speed. Thus, with the engine speed maintained substantially constant by a governer, the available engine horsepower at full throttle is substantially fixed, while the actual delivered horsepower may be smaller, as determined by the traction motor load and throttle position. As shown on thedrawings, the engine It is provided with a multiple compartment carburetor having a plurality of fixed idling Jets in a compartment 25 and a plurality of variable running Jets in a compartment 25a. The running jets are supplied through a fuel inlet conduit 23 and controlled by a throttle valve having an operating lever 26. The idling jets are supplied through a separate fuel inlet conduit 23a provided with a shut-off valve 24 biased to a normally open position. The throttle lever 26 is biased by atension spring 2'! to an idling position with the throttle valve completely closed, and is connected through a. rod 28 and an overtravel mechanism 29 to a fluid pressure governor servo-motor 30. The servo-motor 30 is controlled by a speed responsive apparatus including an engine-driven tachometer generator 3| and a foot pedal 32. The foot pedal I2 determines the speed setting of the speed responsive.

apparatus, and that apparatus controls the servomotor 30 to maintain substantially constant the speed of the engine I at the desired setting. The pedal 32 is biased by a tension spring 32a to 8. released position such that the governor is setfor idling speed.

The servo-motor 30 comprises a reversible fluid pressure motor 30:: and a fluid control valve 30b. The fluid motor 30a includes a reciprocable power piston 33 and is connected by suitable inlet and outlet conduits to. the control valve 30b. The control valve 38b includes a piston valve 34 formed to provide three spaced valve members.

35, 36, and 31 and biased upwardly by'a compression spring 34a. The piston valve 34 is con'-. nected for downward actuation against its bias by a solenoid 38 having a main actuating winding 38 and a stabilizing winding 40. The power piston 33 is arranged to move longitudinally a.

gear rack 4| which meshes with a pinion 42 mounted upon a governor shaft 43. Suitable fluid under pressure, such as oil, from the lubricating system (not shown) of the engine I is supplied to the servo-motor 38 through an inlet conduit 44 and is expelled from the 'motor 38 through.

an outlet conduit 45.

The governor shaft 43 is arranged to drive, through suitable gearing 48, 41, 48, a pair of potentiometers 48 and 58. The purpose of these potentiometers will be more fully described hereinafter. The shaft ,43 also has rigidly-mounted thereon an arm which is resiliently connected, as b a tension spring 52, to a second arm 53 loosely mounted upon the shaft 43. The throttle rod 28 is connected to the loosely mounted arm 53. The arm 53. and hence the engine throttle lever 26, ismovable between predetermined limits fixed by an idling stop 54 and a full throttle stop 55. The arm 5i, which is fixedly attached to the governor shaft 43, is not limited in its movement by the full throttle stop 55 and is thus capable of a certain degree of overtravel beyond the full throttle position of the shaft 43. During such overtravel. the spring 52 between the arms 5| and .53 is stretched and the potentiometers 48 and 50 continue to move with the shaft43. The potentiometer 48 is provided with a dead" section over which it effects no change of potential or its slider 48a. The slider 48a operates over the dead section throughout the entire range of throttle controlling movement of the governor shaft 43, and over the live section of the potentiometer only during overtravel of the governor shaft 43 with respect to the throttle arm 53.

The principal control of the governor mechanism is through the engine tachometer generator 3| and the servomotor control winding 38, the tachometer generator being connected to supply to the winding 38 a voltage proportional to the speed of the engine Ill. The tachometer generator 3i has been shown as a three-phase magneto generator supplying current to a threephase full wave rectifier 58 and from the rectifier 58 to the actuating winding 38 through a plurality of rheostats5l, 58, and 58 in series cir-' cuit relation. The rheostat 58 is controlled by the foot pedal 32 selectably to determine the speed setting of the governing apparatus at the will of an operator.

governor solenoid 38 and to increase the rapidity with which the solenoid 38 responds to changes in engine speed. The rheostat 51 determines minimum running speed and is arranged to be shunted by the normally closed contacts or a "dead man" switch 62. This switch is normally closed and is manually opened by the operator 735 and minimizes hunting of the governor.

a after the engine In is running and before the vehicle is set in motion. Thus the rheostat 58 0 controls the engine idling speed and the rheostat 51 controls'the minimum running speed. The

purpose of such minimum running engine speed is to provide adequate power for braking and steeringeven though the pedal 32 is in its released position.

The stabilizing winding 40 operates in conjunction with the actuating winding 38 to control the servomotor 30 and is connected through a capacitor '61 and a resistor 6'Iabetween one terminal and the sliding contact of the potentiometer 50 geared to the governor shaft 43.

This potentiometeris connected at one terminal to ground and at the other terminal to the posi- -.tive side of a suitable source of unidirectional current supply, such as a battery 63. The battery 63 is connected through a suitable disconnecting switch 54 to a wire 3+, and the potentiometer 58 is connected to the wire B+ through 'a manually operable control switch 65. The condenser 61 in the circuit of the stabilizing winding 48 renders the winding 40 responsive only to changes in the setting of the potentiometer 58 produced by movements of the fluid-pressure power piston 33. The stabilizing current thus produced is proportional in amplitude to the speed of movement of the power piston 33. The

stabilizing winding 40 is so arranged that it transiently opposes any movement of the fluid control piston valve 34 in response to change in the energization of the actuating winding 38. The winding 48, therefore, opposes overshootin The stabilizing winding 40 is shunted by a nonlinear unilateral conducting device, such as a rectifier. 68. The break-down voltage of the rectifier .53 in its conducting direction is such 40 that it does not provide appreciable shunting oi the winding 48 for normal stabilizing currents in either direction. However, in the event that the engine load is dropped very suddenly, as due to a break in the line circuit, a very large transient current would tendto pass through the winding 46 in a direction to oppose the rapidly increasing flux of the'winding 38. Under such conditions the winding 38 is attempting to reduce the engine speed. It is of course desirable to reduce the engine speed as rapidly as possible when the engine speed is thus increasing rapidly. It isthererore desirable at such time to do away with the opposing tendency of the winding 48. The rectifier 68 functions upon ver rapid increase in engine speed to shunt the winding 4|!v thereby to eliminate its normal stabilizing eifect.

To provide for starting and stopping the internal combustion engine I8, I provide a pair of manually operable push buttons Ill and H and an engine starting motor 68 connected to the atlng winding 14 of a starting contactor 15. This energizing circuit may be traced from the wire B+ through the manual switch 66, the contact 12, and the actuating winding 14 to ground.

70 When the starting contactor I5 picks up, it closes its contact 16 to complete an energizing circuit from the wireB-ithrough the engine starting motor 68.

During starting operationthe starting switch 1| also closes its contact 1: to connect the stanseam prises a normally open contact 34 which is con-- meted in parallel circuit relation withthe ,en- 4 bilizing winding 43 of the governor momentarily directly across the battery 35. It will be noted that, with the engine at standstill, the engine lubricating oil in the conduit 44 is under zero pressure, the piston valve 34 is held at the upper limit or its movement by the spring 34a, and the engine throttle lever 26, the governor shaft 43 and the power piston 33 are held in their idling positions by the spring '21. Momentary energization of the winding 43 from the battery during engine cranking forces the piston valve 34 of the servo-motor 33 downward against the bias oi the spring 34a thereby to ensure that the power piston 33 and the throttle control mechanism connected thereto remain'in their idling positions. Were it not for this downward actuation oi the piston valve 34,. the pressure built up in the lubricating oil system by engine cranking would supply oil'under pressure between the control valves 36 and 31 and thus tothe right side of the power piston 33 thereby to move the piston 33 to its extreme left-hand position and the throttle lever 26 to its full open position. It

is undesirable to attempt to start the engine with the throttle fully open and, in fact, many engines will not start with the throttle so positioned. It is to prevent such opening of the throttle beiore'the engine 13 fires that the stabilizing winding 43 is momentarily energized from the battery. When the piston valve 34 is moved to its lowermost position by the coil 43, any oil under pressure in-the conduit 44 is supplied to the left side of the power piston 33 and holds the throttle control mechanism in its idling position shown.

The engine stop switch 13 comprises two normally open contact 11 and 13 and is arranged, when depressed, to'complete through the contact 11 a circuit from the wire B+ through an actuating winding 13 of a fuel cutoff solenoid 33. As indicated upon the drawings, the solenoid 33 is arranged when energized to close the fuel cutoff valve 24 in the engine fuel conduit 23a. The other normally open contact 13 on the engine stop switch 13 lsvarranged to consame manner as the stop switch 13. In so doing nect the governor stabilizing winding 43 directly across the battery in the same manner as the contact 13 of the engine starting switch 1|. The reason for energizing the winding 43 from the engine stop switch 13 is to ensure that the piston valve 34 of the servo-motor 33 will be moved to its lowermost position thereby to move the power piston 33 to its idling position as the engine is brought to standstill. Thus, the contact 11 of the stop switch 13 controls the shutoff valve 24'to'cut of! fuel from the idling jets in the carburetor compartment 25, while the sion spring 34a. When the engine is at standstill the lubricating oil pressure is zero, so that the power piston 33 is not moved to the left even though the valve member 36 is positioned for such movement.

The engine I 3 is provided also with an overspeed switch 3| actuated by a suitable speed re- .sponsive mechanism 32. The switch 3| comsine stop switch contact 13 and a second normally open contact 33 connected in parallel circuit relation with the stop switch contact 11.

ilms, when the engine tends to exceed a predetermined maximum speed, the overspeed contacts 34 and 33 act to stop the engine in the the ove'rspeed contact 33 energizes the cutofi solenoid 33 to cut of! fuel from the idling jets and the contact 34 energizes the stabilizing windin: 43 mm the battery to close the enginev throttle. It will be understood that in operation the overspeed switch 3! is set for a speed considerably higher than normal so that it operates only as an emergency measure to prevent engine the servo-motor 33 simultaneously and momen-.

tarily forced to its lowermost position has already been described. As soon as the engine fires, the

starting switch 1| is released. Steady state energization of the stabilizing winding 43 from the battery is discontinued by opening of the switch 1i and the control piston 34 moves back from its lowermost position to an equilibrium position. This position of equilibrium is that in which the force .of the spring 34a is just balanced'by the opposing force of the main governor actuating winding 33. The force exerted by the winding 33 is dependent upon the engine speed, and the engine speed will now assume a value such that the opposing forces of the coil 39 and the Spring 34a are balanced when the control valve member 36 is centrally positioned with respect to the oil inlet conduit 44. In this mid-position of the piston valve 34,'oil under pressure is supplied in equal quantities to both sides of the valve member 33 by reason of the fact that the oil inlet conduit 44 is slightly larger than the valve member 36 so that the valve 33 is unable fully to block the oil inlet conduit. Therefore, oil in equal quantities is also supplied to both sides of the power piston 33. The oil thus supplied to both sides of the power piston and piston valve efiects a hydraulic balancing of both members without giving rise to any tendency for either member to move in either direction. The continuous leakage of oil past the control valve 36 ensures quick response to any controlling movement of the piston valve 34. i

It will now be evident that the servo-motor 33 will regulate to maintain the engine speed at a desired value. For example, if the engine speed increases for any reason, the energization of the governor actuating winding 33 will be increased and the piston valve 34 will be moved downward. Downward movement of the piston valve 34 closes the fluid connection from the inlet conduit 44 to the right-hand side of the power piston 33 and increases the flow of oil from the conduit 44 to the left side of the piston 33 thereby to move the piston 33 to the right and the engine throttle lever 33 toward its idling position. Inmoving downward, the control valve member 31 uncovers the associated exhaust port to permit exhaust of oil from the right side of the piston 33 to the exhaust port 45 as the piston moves toward the right. If, on the other hand, the engine speed decreases below its desired value for any reason, the energization of the governor winding 33 will decrease so that the spring 34a wfll move the piston valve 34 upward. when the piston valve 34 moves upward, the control valve 33 closes the fluid connection from the inlet conduit 44 to the left side of the piston 33 and admits more oil to the right side of the piston 33 thereby to move the power piston to the left. Simultaneously, the control valve member 35 uncovers the associated exhaust port to admit'oil from the left end of the piston 33 to' the exhaust conduit 45. Movement of the power piston 33 toward the left moves the engine throttle lever 23 toward its full open position thereby to increase the engine speed.

The constant engine speed maintained by the governor mechanism is determined by the rheostats 51, 53, 53, and 33. The rheostats 51 and 58 are set manually to determine the amount of resistance in series with the governor coil 33 with the pedal 32 in its released position. The pedal controlled rheostat 53 is also connected in series circuit relation with the winding 33 and permits selection of the engine speed by the pedal 32 at the will of the operator; The released position of the pedal 32, as determined by the spring 32a is such that the rheostat 53 inserts its minimum resistance in the circuit of the winding 33.

As the pedal 32 is depressed, the rheostat 53 inserts more resistance in series with the winding 39. Since the current in the winding 33 must be the same at any speed maintained in ordertachometer in parallel circuit relation with the winding 33 and the rheostats 51, 53, and 53, determines the proportion of current passing through the winding 33, and hence may be set to require various engine speeds in order to pass the necessary fixed current through the winding at the maximum resistance position of the rheostat The purpose of the overtravel linkage 23 will now be evident. If the load upon the engine I3 is so great that even after the governor has moved the throttle lever 23 to its full open position the engine is still unable to maintain the desired speed, the governor, through the overtravel linkage 23 connected to the governor shaft 43, will move the slider of the potentiometer 43 over the live section of the potentiometer without effecting further movement of the engine throttle. Movement of the potentiometer slider 43a in overtravel over the liv section of the potentiometer 43 reduces the excitation of the generator exciter I3, and hence the generator I2, in a manner which will be more fully described hereinafter. Such reduction of the generator excitation reduces the load upon the engine and'permits the'engine to attain the desired speed. By-

horsepower'output of the engine I3, thereby to prevent slight engine stalling within this range ableengine horsepower over a wide range of vehicle speed and generator load current.

The electric traction motor control system forming part of the complete power system illustrated at Fig. 1 is shown only in broad outline.

tially independent of the back electromotive.

force of the traction motors I3 and II. The voltampere characteristic of the generator I2 at any predetermined engine speed is dependent upon the energization of the main generator field exciting winding 33 which is, in turn, controlled by the energization of a plurality of field windings 3!, 32 and 34 on the exciter l3.

Preferably, the exciter I3 is a direct .current generator of the type described and claimed in Patent 2,227,992 issued to Ernst I". W. Alexanderson and Martin A. Edwards on January 'I, 1341. Such a generator is of the cross armature reaction excited, direct armature reaction compensated type, known as an amplidyne, and is provided with a pair of current supply brushes 35 and a pair of short-circuited brushes 33. The control field winding 34 is arranged to generate a voltage between the short-circuited'brushes 33 and the cross armature reaction of the current flowing through the short-circuited connection as a result of this voltage sets up a flux in such a direction as to provide an output voltage at the load brushes 35 which is proportional to the excitation of the machine along its short-circuit axis. The field winding 32 is a series load compensating winding for neutralizing the armature reaction of the exciter load current. One of the desirable characteristics of an amplidyne-generator of this type is that its output voltage responds very rapidly and with a high degree of amplification to any change in the energization of its control field windings.

The generator exciter main control field winding .34 is energized from the battery 63 through the governor potentiometer 43. It will be observed that the potentiometer 43 is connected to the wire B+ through a resistor I33 and to ground through a resistor 33 and a manual control switch I32. The control field winding 34 is connected in series with a res stor I3I between the grounded side of the resistor 33 and the slider 43a of the potentiometer 43. It will be understood of course that the resistors 33 and IN are grounded through the control switch I32 only when the switch I32 is in its closed running position.

In connection with the above description of the energization of the control field winding 34,

it will be borne in mind that the battery energization of this field winding ismaintained constant by the potentiometer 43 over the full range of engine throttle variation. The battery energization of the winding 34 is reduced by the potentiometer, thereby to reduce the main generator excitation and output voltage, only when the load upon the engine is such that the desired speed cannot be maintained even with the throttle fully open. This field reducing action of the governor controlled potentiometer 43 takes place only during overtravel operation of the governor and is of a regulatory nature, so that the power generator is maintained substan-' tially equal to the available power output or the engine.

In view of the foregoing detailed explanation "may be set in operation by closing the switches 64 and 66 and the engine starting switch II. The manner in which the switch H starts the engine by energizing the starting motor 69 and simultaneously moving the governor piston valve 34 to maintain the governor power piston 33 in its idling position has already been described. Motoring operation is now initiated by closing the line switch 22 to complete the motor circuit, closing the switch |02 to connect the potentiometer 49 across the battery 63 thereby to complete an energizing circuit for the main control field winding 94 of the generator exciter l3, and opening the switch 62 to unshunt the governor rheostat 51. It will be understood that in practice the switches 22, I02 and 32 may be controlled by a suitable manual sequence controller of any well known t p With the generator l2 excited, current fiows in the motor circuit and the vehicle begins to accelerate irom standstill in the forward direction.

If it is desired to increase the speed of thevehicle, the accelerator pedal 32 is depressed to increase the resistance interposed by the rheostat 59 in the circuit of the governor actuating winding 39. The consequent decrease in the energization of the winding 39 causes the governor piston valve 34 to move upward to supply oil to the right side of the power piston 33 and thereby to open the engine throttle. During throttle opening movement, the governor potentiometer 50 is changing the potential impressed upon the condenser 61, thereby to produce in the governor stabilizing winding 40 a transient current having a magnitude proportional to the speed of the power piston 33 and in a direction tending to oppose the upward movement of the governor piston valve 34. This opposing action of the stabilizing winding 40 is effective only so long as the governor power piston 33 is in motion. When the engine attains such a speed that the predetermined normal current is again established through the governor actuating winding 39, the governor piston valve 34 again assumes its normal mid-position and, by regulating action, maintains the engine speed at'the new value.

The action of the rectifier 63 in shunting the governor stabilizing winding 40 to prevent engine runaway has already been described.

In order to stop the engine, the push button 10 is depressed to complete an energizing circuit spring 21 and the governor piston valve 34 is held in its uppermost position by the spring 34a.

In view of the foregoing explanation of my invention as embodied in the power system of Fig. 1, the modified forms of the invention illustrated at Figs. 2-4, inclusive, will be readily understood. In these latter figures, I have illustrated various control circuit arrangements for the governor actuating and stabilizing windings 39 and 40, respectively. While their arrangement is diflerent,

the various elements of the circuits of Figs. 2, 3,

and 4 correspond to similar elements of Fig. 1, and like arts have been assigned the same reference numerals.

At Fig. 2, I have shown an embodiment of my invention in which the voltage of the tachometer generator 3| is balanced against a selectable portion of an opposing voltage derived from the battery 63. In this case, the rheostat 59 is connected as a potentiometer acr'oss the battery 33 and the series circuit through the governor actuating winding 39 is connected to the potentiometer slider to include in the circuit a desired portion of the battery voltage in opposing relation to the voltage of the tachometer generator 3 I At Fig. 2, the governor rheostat 50 is connected across the battery 63 and to the governor stabilizing winding 40 through the capacitor 61 in the same manner as shown in Fig. 1.

At Fig. 2, I have shown a condenser 3| connected across only thecontrol rheostats 51 and 53 in place of the condenser SI of Fig. 1 connected across these rheostats and also the rheostat 39. With the connection of condenser 6! shown at Fig. 2, this condenser has no effect upon the rapidity with which changes in foot-pedal position are felt by the actuating winding 39, but functions only under changing speed conditions to prevent v hunting of the governor by accelerating the effect of tachometer voltage changes upon the governor actuating winding 39.

At Fig. 3, I have shown an embodiment of my invention in which the unidirectional current supply for the stabilizing winding 40 of the governor is derived from the tachometer generator 3| and introduced into the stabilizing winding through a variable coupling transformer 200, thereby rendering the governor independent of outside power sources. The variable coupling transformer 200 comprises a movable primary winding 20! and a stationary secondary winding 202. The primary winding 20l is connected for movement by the power piston 33 of the governor its for the shut-off solenoid 30 and momentarily to energize the governor stabilizing (winding 40 from the battery. As previously described, the shut- .oiI solenoid 80 actuates the valve 24 to shut oi! and the secondary winding 202 is connected through a suitable full wave rectifier 203 and the condenser 61 to the stabilizing winding 40 of the governor. The primary winding 2! of the transformer is energized through a fixed reactance 204 from one phase of the alternating current output of the tachometer generator 3 I, so that the transformer primary current is substantially constant at any predetermined engine speed regardless of the slight speed variations effecting regulating operation of the governor. Therefore, for any predetermined speed setting of the governor, the secondary voltage of the variable coupling transformer 200 is independent of engine speed and is dependent only upon the degree of coupling as controlled by the power piston 33. It will now be evident that movement of the power piston 33 in governor operation eflects a change in charge ofthe condenser 61 and causes a transient flow of current through the governor stabilizing winding 40 to oppose the controlling movement of the i of the prime movers is provided with a governor structurally similar to that shown at Fig. l and electrically connected to incorporate features of both Figs. 2 and 3. The parts of the governor associated with the engine II) have been assigned reference numerals the same as those at Fig. 3, and the parts of the governor associated with a second engine I'll have been assigned like reference numerals similarly distinguished.

.At Fig. 4, the circuit for each of the governor actuating windings 39 and 39' is connected in the manner of that shown at Fig. 2 to include, in opposing relation to the tachometer generator, a selectable portion of the unidirectional battery voltage appearing across the rheostat 59 connected as a potentiometer. The circuit of the governor winding 39 also includes a series resistor 2H) and the circuit the governor actuating winding 39' includes a se ies resistor 2"). Specifically, the energizing c uit for the governor actuating winding 39 my be traced from the positive terminal of the rectifier 56 through the upper portion of the potentiometer 59, the resistor M0, the actuating winding 39, and the rheostats 51 and 58 to the negative terminal of the rectifier 56. The energizing circuit for the governor actuating winding 39' may be similarly traced from the rectifier 56'.

The stabilizing windings 40 and 40 of Fig. 4 are each energized through a variable coupling transformer and a rectifier bridge in the manner heretofore described. in connection with Fig.. 3. The variable coupling transformer 209 is controlled by the governor associated with the engine 10, and the variable transformer 200' is controlled by the Eovemor associated with the engine III.

In order that the engines I0 and I0 shall share the load equally or proportionately, each engine governor is provided with an additional or paralleling winding connected for response to the difference of the currents flowing in the circuits of the governor actuating windings 39 and 39'. Speciflcally, there is associated with the governor actuating winding 39 a paralleling winding 2 and with the governor actuating winding 39' a paralleling winding 2| i. The paralleling windings 2! I and 2| l' are connected in series circuit relation and to measure the diflerence in voltage drops across the resistors 2 I II and 2 l 9'.

In operation, it will be understood that, with both the engines I9 and Ill operating exactly at the desired speed, the currents in the circuits of the governor actuating windings 99 and 39' are equal, so that no current flows through the paralleling coils 2H and 2H. If now the load upon one engine, for example the engine I0, is decreased so that the engine Ill speeds up, the current through the governor actuating winding 39 and the resistor 2"! increases. The increased current through the winding 99 actuates the governor of the engine Ill to close the engine throttle. At the same time, the increased voltage drop across the resistor 2! causes a flow of diflerential current through the paralleling windings 2H and 2| l' in a direction tending to oppose closin of the throttle Of the engine I0 and to assist 0108-- ing of the throttle of the engine it. In this man- "ner, each engine is prevented from droppin i load and transferring the entire load to the other engine upon the slightest irregularity of operation. The operation is reversed if the engine III is reduced in speed by increased load.

In all the embodiments of my invention described above, I have utilized a three-phase alternating current tachometer generator in connection with a three-phase rectifier for obtaining a unidirectional voltage proportional to engine speed. It will be understood by those skilled in the art that with such an arrangement a certain amount of alternating or ripple voltage appear in the direct current output continuously traversing the governor actuating winding 39. I have found that this ripple current is highly desirable by reason of the fact that it produces a very slight but continuous oscillation of the governor piston valve 34 about a mean control position determined by the magnitude of the direct current component in the coil 99. With the piston valve 94 thus kept in continuous motion, the friction of the piston in its cylinder is considerably reduced. The same effect may, if desired, be produced by a separate coil on-the solenoid 38 energized from the alternating current output of the way of illustration, many modifications will occur I to those skilled in the art and I therefore wish to have it understood that I intend in the appended claims to cover all such modifications as fall within the true spirit and scope of my inven tion. I

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a regulating apparatus for a prime mover having a throttle valve, 9. fluid pressure motor connected to actuate said throttle valve, 9. movable fluid control valve responsive to the speed of said prime mover for controlling said fluid motor, and means transiently-responsive to movement of said fluid motor for transiently opposing movement of said control valve.

2. In a regulating apparatus for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a movable fluid control valve responsive to-the speed of said prime mover for eflecting operation of said fluid motor at a speed proportional to displacement of the speed oi saidprime mover from a predetermined desired speed, and means responsive to the speed of said fluid motor for transiently and proportionately opposing controlling movement of said control valve.

3. In a regulating apparatus for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a movable fluid control valve for eflecting operation of said fluid motor, electromagnetic means responsive to the speed of said prime mover for actuside of normally balanced mid-positionto eflect operation of said motor in opposite directions,

electromagnetic means responsive to the speed of said prime mover for controlling said control valve, and electromagnetic means responsive to movement 0! said fluid motor in either direction to oppose controlling movement or said control valve.

5. In a regulating apparatus tor a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve thereby to control the speed of said prime mover, a fluid control valve movable to either side of a normally balanced mid-position to eflect operation of said motor in opposite directions,

. means for biasing said control valve in one direction, electromagnetic means responsive to the speed 01' said prime mover ior moving said control valve in the opposite direction, and electromagnetic means responsive to movement or said fluid motorin either direction to oppose the controlling action oi' said speed responsive electromagnetic means.

6. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve thereby to control the speed of said prime mover, a fluid control valve movable to either side 01' the mid-position to eflect operation of said motor in opposite directions, means for biasing said control valve in one direction, an electromagnet having an actuating winding energized in accordance with the speed of said prime mover i'or moving said control valve in the opposite direction, said electromagnet' normally holding said control valve balanced in said mid-position when the speed 01 said prime mover is at a predetermined desired value, a stabilizing winding associated with said electromagnet, means for energizing said stabilizing winding including a source of direct current supply and a blocking condenser, and means responsive to movement of said fluid motor in either direction-for changing the voltage of said direct current supply source in a sense to energize said stabilizing winding to oppose the controlling influence oi said actuating winding.

'7. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve, a fluid control valve, means including an electromagnet energized in accordance with the speed of said prime mover for regulating said control valve about a normally balanced midposition to effect operation of said fluid motor at a speed proportional to the deviation of said prime mover from a predetermined speed, said fluid motor being maintained at standstill when thereof, a fluid pressure motor connected to actuate said throttle valve, an electromagnetic fluid control valve movable to eflect operation oi said fluid motor, means for supplying to said electromagnet an energizing current having a direct current component proportional to the p ed of said prime mover and an appreciable alternating current component, said alternating current component'being eiiective continuously to oscillate said control valve about a mean controlling position without significantly afiecting the supply or fluid to said fluid motor thereby to minimize friction in said control valve,

10. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve thereby to control the speed of said prime mover, a fluid control valve movable to either side of a balanced midposition to supply fluid to said motor through alternative paths thereby to effect operation of said fluid motor inopposite directions, said control valve being arranged when in said midposition to supply fluid to said motor equally through both said alternative paths thereby hydraulically to balance said motor, means responsive to the speed of said prime mover for regulating said control valve about said midposition to maintain said speed substantially constant, and means transiently responsive to movement of said fluid motor in either direction transiently to oppose controlling movement of said control valve.

11. In a regulating apparatus for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a movable control valve responsive to the speed of said prime mover for controlling said fluid motor, stabilizing means responsive to the speed of said fluid motor transiently to .oppose movementof said control valve, and means operable upon the occurrence of a predetermined high fluid motor speed to disable said stabilizing means.

In a regulating apparatus for a prime mover having a, throttle valve, 2. fluid pressure motor connected to actuate said throttle valve,

a movable control valve responsive to the speed of said prime mover for controlling said fluid .said control valve is in said mid-position, electromagnetic stabilizing means associated with said electromagnet, and means including a source of electric current supply responsive to movement o'i' said fluid motor transiently to energize said stabilizing means in accordance with the speed of said fluid motor in either direction and in a sense always to oppose controlling movement of said control valve.

8. In a regulating apparatus for a prime mover having a throttle valve to control the speed thereof, a fluid pressure motor connected toactuate said throttle valve, an electromagnetic fluid control valve movable to effect operation of said fluid motor, an alternating current tachometer generator driven by said prime mover and connected to energize said electromagnetic valve, and electromagnetic means associated with said 'alternating current generator continuously to oscillate said control valve at relatively high fre- "quency without appreciably aflecting the supply of fluid to said prime mover.

9. In a regulating apparatus for a prime mover having a throttle valve to control the speed motor to maintain said prime mover speed substantially constant at a desired value, stabilizing means responsive to the speed of said fluid motor transiently to oppose controlling movement of said valve, and means responsive to a predetermined deviation of said, prime mover speed from said desired value for disabling said stabilizing means.

13. In a regulating apparatus for a prime mover having a throttle valve, 9. fluid pressure motor connected to actuate said throttle valve, a movable control valve responsive to the speed of said prime mover for controlling said fluid motor to maintain said prime mover speed substantially constant at a desired value, said fluid motor speed being proportional to the deviation of said prime mover speed from said desired value, stabilizing means responsive to the speed of said fluid-motor transiently to oppose controlling movement of said valve, and non-linear means responsive to said fluid motor speed for disabling said stabilizing means upon the occurrence 01' a predetermined deviation of prime mover speed.

14. In a regulating apparatus for a prime mover having a. throttle valve, a fluid pressure motor connected to actuate said throttle valve,

a movable control valve re p nsive to the p ed of said prime mover for effecting operation of said fluid motor at a speed proportional to displacement of the speed or said prime mover from ,a predetermined desired speed, stabilizing pressure motor connected to actuate said throttle valve thereb to control the speed of said prime mover, a fluid control valve movable to either side of a balanced mid-position to effect operation of said motor in opposite directions, electromagnetic means responsive to the speed of said prime mover for controlling said control valve to maintain the speed or said prime mover at a predetermined value, second electromagnetic means responsive to movement of said fluid motor in either direction to oppose controlling movement of said control valve, and non-linear unilateral conducting means connected to shunt said second electromagnetic means only upon predetermined increase of said prime mover speed above said predetermined value thereby to facilitate rapid closure of said throttle valve.

16. In a regulating apparatus for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a movable control valve responsive to the speed of said prime mover for controlling said fluid motor, stabilizing means responsive to the speed of saidfluid motor transiently to oppose controlling movement of said throttle valve, and means responsive to excessive overspeeding of said prime mover for controlling said stabilizing means to aid closing movement of said throttle valve.

17. Ina regulating apparatus fora prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a control valve for effecting operation of said fluid motor, electromagnetic means responsive to the speed of said prime mover for controlling said control valve to maintain the speed of said prime mover substantially constant, electromagnetic stabilizin means energized in response to movement of said fluid motor transiently to oppose controllin movement of said control valve, and means responsive to excessive overspeeding or said prime mover to energize said stabilizing means in a sense positively to aid closing movement of said throttle valve.

18. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve, a fluid control valve movable to either side of a balanced mid-position to efiect operation of said fluid motor in opposite directions, electromagnetic means responsive to the speed of said prime mover for controlling said throttle valve to maintain the speed of said prime mover substantially constant at a desired value, second electromagnetic means responsive to movement of said fluid motor in either direction'transiently to oppose controlling movement of said control valve, and means responsive to a predetermined excessive overspeeding of said prime mover continuously a,aoo,oss

in a sense to eflect rapid throttling of said prime mover. v

19. In a regulating apparatus for a prime mover having a throttle valve movable between idling and fully open positions, a reversible fluid pressure motor connected to actuate said throttle valve, a fluid control valve biased to a position to maintain said fluid motor: in a position fully to open'said throttle valve, electromagnetic means responsive to the speed 01' said prime mover for moving said control-valve against its bias and etfecting regulation oi. said valve about a balanced midposition, means for cranking said engine, and

means operable in conjunction with said crank-- ing means for forcibly moving said control valve against its bias to a position to maintain said throttle valve in said idling position.

20. In a regulating apparatus for a prime mover having a throttle'valve movable between idling and fully open positions, a reversible fluid pressure motor connected. to actuate said throttle valve, a fluid control valve biased to a position to maintain said fluid motor in position fully to open said throttle valve, means responsive to the speed of said prime mover for effecting regulation of said control valve about a normally'balanced midposition, electromagnetic stabilizing means responsive to movement of said fluid motor to oppose controlling movement of said control valve, means for cranking said engine, and means v operable in conjunction with said cranking means for energizing said stabilizing means from a separate source ofconstant electric current supply to movesaid control valve against its bias to a position to maintain said throttle valve in said idling position. V

21. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle 40 valve, a fluid control valve biased to a position to till maintain said fluid motor in position fully to open said throttle valve, electromagnetic means responsive to the speed of saidprime mover for effecting regulation of said control valve about a normally balanced midposition, and means indee pendent of said electromagnetic means for moving said control valve against its bias to a position to effect closing movement of said throttle valve for stopping said prime mover.

22. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve, 9. fluid control valve biased to a position to maintain said fluid motor in position fully to open said throttle valve, electromagnetic means responsive to the speed of said prime mover for effecting regulation or said control valve about a balanced midposition, electromagnetic stabilizing means transiently responsive to movement of said fluid motor to oppose controlling movement of said control valve, and means for stopping said prime mover including a separate source of substantially constant electric current supp y for continuously energizing said stabilizing means to move said control valve against its bias to a position to eifect throttle closing operation of said fluid motor. I

23. In a regulating apparatus for a prime mover having a throttle valve, a reversible fluid pressure motor connected to actuate said throttle valve, a source of fluid pressure supply responsive to operation of said prime mover, a fluid control valve biased to aposition to maintain said fluid motor in position fully to open said throttle to energize said econd electromagnetic means valve, means for biasing said throttle valve and said fluid motor to an idling position, electromagnetic means responsive to the speed of said prime mover for efiecting regulation of said control valve about a balanced midposition to eflect speed regulating operation of said fluid motor during running of said prime mover, electromagnetic stabilizing means for said control valve responsive to regulating movement of said fluid motor transiently to oppose controlling movement of said control valve, means for cranking said engine, means operable in conjunction with said cranking means for continuously energizing said stabilizing means independently of said fluid motor to move said control valve to a position to maintain said throttle valve in said idling position, and means for stopping said engine including additional means for continuously energizing said t bilizing means to move said throttle valve to said idling position, o

24. In a governing system for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a fluid control valve biased for movement in one direction, means including an electromagnet having an actuating winding for moving said control valve against its bias and normally maintaining said control valve in a balanced midposition, means including a manually controllable variable resistor for energizing said actuating winding in accordance with the speed of said prime mover, and time element means asociated with said resistor for controlling the energization of said actuating winding in accordance with rate of change of prime mover speed and resistance value.

25. In a governing system for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, 9. fluid control valve biased for movement in one direction, means including an electromagnet. having an actuating winding for moving said control valve against its bias and normally maintaining said control valve in a balanced mid-position, means for energizing saidactuating winding in accordance with the speed of said prime mover, manually controllable resistance means in series circuit relation with said actuating winding for controlling the speed of said prime mover, and time element means associated with said energizing means and said resistance means transiently to delay the effect of resistance changes upon said actuating winding and to acceleratethe effect of prime mover speed changes upon said accelerating winding thereby to prevent hunting of said governing system.

26. In a governing system for a prime mover having a throttle valve, a fluid pressure motor connected to actuate said throttle valve, a fluid connected to actuate said throttle valve, 9, fluid control valve biased for movement in one direction, means including an eiectromagnet having an actuating winding for moving said control valve against its bias and normally maintaining said control valve in a balanced mid position, a tachometer generator for energizing said actuating winding in accordance with the speed of said prime mover to effect regulation of said control valve about said mid-position thereby to maintain the speed of said prime mover substantially constant, manually controllable variable resistance means connected in series circuit relation with said actuating winding to select the governed speed of said prime mover, and second manually controllable variable resistance means connected in shunt circuit relation with said actuating winding to determine the maximum governed speed or said prime mover.

28. In a governing system for a plurality of prime movers connected to supply power in parallel load relation, a throttle valve associated with each of said prime movers, a fluid pressure motor connected to actuate each of said throttle valves, a movable fluid control valve associated with each pi said fluid motors, means for biasing each of said control valves to effect operation 01' the associated fluid motor in one direction, electromagnetic means including an actuating winding for moving each of said control valves against its bias to eflect operation of the associated fluid motor .in the opposite direction, means for energizing each of said actuating windings in accordance with the speed of the prime mover associated therewith, said electromagnetic means holding each of said control valves in a,

balanced mid-position when the associated prime mover is running at a predetermined desired speed, and means for stabilizing the load distri- 40 bution between said prime movers comprising electromagnetic means for simultaneously controlling all ol' said control valves in accordance with a difference in the amount of deviation of said prime movers from their predetermined desired speeds.

29. In a governing system for a plurality of prime movers connected to supply power in parallel load relation, 9. throttle valve associated with each of said prime movers, a fluid pressure motor connected to actuate each of said throttle valves, a movable fluid control valve associated with each of said fluid motors, means for biasing each of said control valves to elect operation of the associated fluid motor in one direction, electromagnetic means including an actuating windcontrol valve biased for movement in one direction, means including an electromagnet having an actuating winding for moving said control valve against its bias and normally maintaining said control valve in a balanced mid-position, means ing for moving each of said control valves against its bias to effect operation of the associated fluid motor in the opposite direction, means for energizing each of said actuating windings in accordance with the speed of the prime mover associated therewith, said actuating windings carrying equal currents and holding the associated control valve in a balanced mid-position when the connected prime mover is running at a predetermined desired speed, and means responsive to a difference of the currents in said actuating windings for simultaneously controlling all of said control valves to stabilize the distribution of load upon the said prime movers.

30. In a governingsystem for a pair of prime movers connected to supply power in parallel load relation, a throttle valve associated with each of said prime movers, a fluid motor connected to actuate each of said throttle valves, a movable control valve associated with each of said fluid motors, means for biasing'each of said control valves'toefiect operation or the associated fluid motor in one direction, electromagnetic means including an actuating winding iormoving each of said control valves against its bias to effect operation of the associated fluid motor in the 0pposite direction, means for energizing each of said actuating windings in accordance with the speed of the associated prime mover, said actuating windingscarrying equal currents and holding 19 said control valves in balanced mid-positions 4 when the associated prime movers are running at predetermined desired speeds, and means responsive to the difierence of the currentsin said actuating windings for opposing controlling ac- 

